lance_core/utils/
hash.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright The Lance Authors
3
4use std::hash::Hasher;
5
6/// A wrapper for `&[u8]` to allow byte slices as hash keys.
7///
8/// ```
9/// use lance_core::utils::hash::U8SliceKey;
10/// use std::collections::HashMap;
11///
12/// let mut map: HashMap<U8SliceKey, i32> = HashMap::new();
13/// map.insert(U8SliceKey(&[1, 2, 3]), 42);
14///
15/// assert_eq!(map.get(&U8SliceKey(&[1, 2, 3])), Some(&42));
16/// assert_eq!(map.get(&U8SliceKey(&[1, 2, 4])), None);
17///
18/// // Equality is based on slice contents
19/// assert_eq!(U8SliceKey(&[1, 2, 3]), U8SliceKey(&[1, 2, 3]));
20/// assert_ne!(U8SliceKey(&[1, 2, 3]), U8SliceKey(&[1, 2, 4]));
21/// ```
22#[derive(Debug, Eq)]
23pub struct U8SliceKey<'a>(pub &'a [u8]);
24
25impl PartialEq for U8SliceKey<'_> {
26    fn eq(&self, other: &Self) -> bool {
27        self.0 == other.0
28    }
29}
30
31impl std::hash::Hash for U8SliceKey<'_> {
32    fn hash<H: Hasher>(&self, state: &mut H) {
33        self.0.hash(state);
34    }
35}
36
37#[cfg(test)]
38mod tests {
39    use super::*;
40    use std::collections::HashMap;
41
42    #[test]
43    fn test_u8_slice_key() {
44        // Test cases not in doctest: key not found, inequality
45        let mut map = HashMap::new();
46        map.insert(U8SliceKey(&[1, 2, 3]), 42);
47        assert_eq!(map.get(&U8SliceKey(&[4, 5, 6])), None);
48        assert_ne!(U8SliceKey(&[1]), U8SliceKey(&[2]));
49    }
50}
lance_core/utils/hash.rs

lance_core/utils/
hash.rs
